Huawei Technologies Co., Limited

Huawei Digital Power Technologies Co., Ltd.

Fangcheng Liu

Kai Xin

Yunfeng Liu

Xiongfei Wang

Haibin Guo

Lei Shi

Wei Li

Xinyu Yu

Kun Wang

Wuhua Li

Jianwen Wang

Dengfeng Li

Yingyong He

Fuqiang Xu

Lei Jiang

Wanyuan Qu

Teng Liu

Yang Han

Hongwen Yuan

Dongsheng Yang

An islanding detection method includes: an alternating current frequency of an inverter is monitored. The alternating current frequency fluctuates within a preset range when in a normal mode. When an instantaneous shifting value of the alternating current frequency exceeds the preset range, a frequency detected before instantaneous shifting is a first frequency. When a frequency in first frequency data within a first preset time period is greater than or less than only the first frequency, an alternating current frequency detected when the first preset time period ends is a second frequency. Output power of the inverter is continuously adjusted based on a change in the current alternating current frequency. When a frequency in second frequency data within a second preset time period is greater than or less than only the second frequency, it may be indicated in time that islanding occurs in the inverter, and an islanding status is reported.

Islanding detection method and apparatus

This application provides a vehicle and a control method for a vehicle suspension. The vehicle includes a first component, a second component, and a vehicle suspension. The vehicle suspension is located between the first component and the second component. The first component is a component that the vehicle suspension bears, the second component is configured to bear the vehicle suspension and the first component, and the vehicle suspension includes a variable damper connected between the first component and the second component. The variable damper is configured to provide a first force to the first component based on a first acceleration of the first component, to control a displacement of the first component relative to the second component in a height direction of the vehicle. In the embodiments of this application, bumps in a driving process of the vehicle can be effectively reduced, so that vehicle ride comfort is improved.

Vehicle, control method for vehicle suspension, and related device

A voltage conversion circuit includes: an inductor, a first switch module, N second switch modules connected in series, N third switch modules connected in series, and N&#x2212;1 flying capacitors. One terminal of the first switch module is separately connected to one terminal of the N second switch modules connected in series and one terminal of the N third switch modules connected in series. The other terminal of the N third switch modules connected in series is connected to a positive electrode of a high-voltage power supply. The other terminal of the first switch module and the other terminal of the N second switch modules connected in series are connected to a negative electrode of the high-voltage power supply. A low-voltage power supply is connected to the two terminals of the first switch module through the inductor.

Voltage conversion circuit and power supply system

A method for processing a direct current electric arc and an apparatus, includes: obtaining a first current which is a direct current input current of a direct current cable of a photovoltaic cell system; obtaining a second current, where the second current is a direct current common mode current of a direct current cable or an alternating current common mode current of an alternating current cable; calculating a correlation coefficient between a frequency domain component of the first current and a frequency domain component of the second current; and when determining that the first current meets an electric arc occurrence condition and the correlation coefficient is greater than or equal to a preset coefficient threshold, skipping sending a direct current electric arc fault alarm. The correlation coefficient is used to reflect a proportion of common mode noise generated by the second current, and the preset coefficient threshold is set.

Method for processing direct current electric arc and apparatus

One example method includes obtaining output powers at initial scanning points of photovoltaic strings in a first group and a second group. The output powers at the initial scan points of the photovoltaic strings in the first group can then be controlled to sequentially decrease, and the output powers at the initial scan points of the photovoltaic strings in the second group can then be controlled to sequentially increase. Scanning can then be performed in the initial scanning direction starting from output voltages corresponding to the output powers at the initial scan points of the first group. Scanning can then be performed in the initial scanning direction starting from output voltages corresponding to the output powers at the initial scan points of the second group, where output powers of the first group and the second group are kept to compensate each other during IV curve scanning.

Intensity of current-voltage curve scanning method for photovoltaic string, converter, and system

A method for synchronizing PWM control signals of inverters, an inverter, and a power grid system are disclosed, so that PWM control signals of inverters connected to a power grid can be synchronized. A direct current voltage terminal of the inverter is connected to an external power supply, and an alternating current voltage terminal of the inverter is connected to an alternating current point of common coupling of a power grid, and the method includes: obtaining a phase of an alternating current voltage of the power grid (S); determining a time period during which the phase of the alternating current voltage varies within a preset phase threshold interval; calculating a period of a preset carrier wave based on a preset carrier wave ratio and the time period (S); and generating a PWM control signal of the inverter based on a PWM modulation signal and a preset carrier wave (S).

Method for synchronizing PWM control signals of inverters, inverter, and power grid system

A control method for a string inverter, comprising: in a current/voltage (IV) curve scanning process, controlling an output power of an inverter circuit to be a specified power reference value, and controlling an output voltage of each non-IV curve scanning direct current (DC) to DC (DC-DC) circuit to be a specified voltage reference value, where the specified power reference value is less than or equal to a sum of input powers of all non-IV curve scanning DC-DC circuits the before IV curve scanning process, and where the specified voltage reference value is greater than or equal to a preset percentage of a maximum value in open-circuit voltages, before the IV curve scanning process, of photovoltaic strings connected to all IV curve scanning DC-DC circuits.

Control method and controller for string inverter, inverter, and inverter system

A control method and apparatus for a single-phase five-level converter are provided. The method includes: obtaining a first-phase initial modulated wave and a second-phase initial modulated wave of the single-phase five-level converter; obtaining a first-level modulated wave, a second-level modulated wave, a third-level modulated wave, a fourth-level modulated wave, and a fifth-level modulated wave that are output by the single-phase five-level converter; calculating the first-level modulated wave, the second-level modulated wave, the third-level modulated wave, the fourth-level modulated wave, the fifth-level modulated wave, the first-phase initial modulated wave, and the second-phase initial modulated wave, to obtain a common-mode modulated wave of the single-phase five-level converter; and calculating the first-phase initial modulated wave, the second-phase initial modulated wave, and the common-mode modulated wave, to obtain a pulse-width modulated wave of the single-phase five-level converter. Implementing the embodiments of this application can increase a system response speed and improve system reliability.

Control method and apparatus for common-mode modulated wave of single-phase five-level inverter

This application discloses an apparatus, an inverter system, and a method for synchronizing carriers. The apparatus includes a modulation unit, a current processing unit, and a control unit. The control unit can adjust, based on a change trend between an amplitude of a first harmonic current and an amplitude of a second harmonic current and a change trend between a phase of a first carrier and a phase of a second carrier, a phase of an input carrier input into the modulation unit, to decrease an amplitude of a harmonic current output by an inverter and improve stability of a distributed power supply system. Further, a prior-art problem that impact of a harmonic current on a power supply system cannot be reduced by synchronizing carriers in a process of synchronizing carriers based on a zero sequence current is avoided, thereby improving the stability of the distributed power supply system.

Apparatus, inverter system, and method for synchronizing carriers

A camera module includes a lens and a voice coil motor (VCM), and the lens is placed in the VCM, where a first portion of an inner side of the VCM is attached to a first portion of an outer side of the lens, and a second portion of the inner side of the VCM is provided with a screw thread structure recessed relative to the first portion of the inner side of the VCM. The screw thread structure and a second portion of the outer side of the lens form a groove portion, and the groove portion is filled with adhesive. The first portion of the VCM is a lower portion, and the second portion of the VCM is an upper portion. The first portion of the lens is a lower portion, and the second portion of the lens is an upper portion.

Camera module and terminal

Embodiments of this application provide a phase-locking apparatus and a phase-locking method. The phase-locking apparatus includes an amplitude adjustment unit, an amplitude and phase detector connected to the amplitude adjustment unit, a first loop filter connected to the amplitude and phase detector, a second loop filter connected to the amplitude and phase detector, a first oscillator connected to the first loop filter, and a second oscillator connected to the second loop filter. The amplitude adjustment unit, the amplitude and phase detector, the first loop filter, and the first oscillator form a loop; and the amplitude and phase detector, the second loop filter, and the second oscillator form another loop. According to the embodiments of this application, a dual-loop structure of the phase-locking apparatus can weaken frequency coupling between a positive-sequence component generated by the phase-locking apparatus and a negative-sequence component generated by the phase-locking apparatus.

Phase-locking apparatus and phase-locking method

A three-phase converter configured to be coupled between a direct current system and an alternating current system to perform interconversion between a direct current and an alternating current, where the three-phase converter includes a switching network, a three-phase filter coupled to the switching network, a sampling circuit coupled to the three-phase filter, a control circuit coupled to the three-phase sampling circuit, an active damping circuit coupled to the control circuit and the sampling circuit, and a modulation circuit coupled between the active damping circuit and the switching network, where the sampling circuit is configured to obtain three-phase currents in the three-phase filter, and send the three-phase currents to the active damping circuit, the active damping circuit is configured to obtain new three-phase modulated waves according to the three-phase currents, and transmit the new three-phase modulated waves to the modulation circuit.

Three-phase converter with zero-sequence regulation

A single-phase converter control method and apparatus, includes calculating on a voltage corresponding to a first level output by a single-phase converter, a voltage corresponding to a second level output by the single-phase converter, and a voltage reference value about the voltage corresponding to the first level and the voltage corresponding to the second level to obtain a common-mode modulated-wave change rate of the single-phase converter, where the first level is a direct-current-side positive-bus level, and the second level is a direct-current-side negative-bus level, calculating on a first-phase initial modulated wave of the single-phase converter, a second-phase initial modulated wave of the single-phase converter, and the common-mode modulated-wave change rate to obtain a common-mode modulated wave of the single-phase converter, and calculating on the first-phase initial modulated wave, the second-phase initial modulated wave, and the common-mode modulated wave to obtain a pulse width modulated wave of the single-phase converter.

Single-phase converter control method and apparatus

A pulse width modulation method, a pulse width modulation system, and a controller are provided, which change a change rate of a common-mode component of a three-phase converter upon a change of a converter modulation degree, thereby improving stability and harmonic characteristics of the three-phase converter and implementing flexible adaptive adjustment. An example pulse width modulation method includes: obtaining initial three-phase modulation waves and a converter modulation degree; calculating a common-mode-component change-rate adjustment coefficient based on preset modulation parameters and the converter modulation degree; selecting a modulation wave having a minimum absolute value from the modulation wave set as a common-mode modulation wave; and performing waveform superposition on the initial three-phase modulation waves and the common-mode modulation wave to obtain output three-phase modulation waves.

Pulse width modulation method, pulse width modulation system, and controller

The present disclosure relates to the field of inverters, and to a method for detecting grid connection stability of an inverter and an inverter. The method includes: detecting a line voltage and a current of the alternating current port to obtain a first group of line voltage values and a first group of current values; detecting the line voltage and the current of the alternating current port to obtain a second group of line voltage values and a second group of current values; obtaining an equivalent impedance matrix of the power grid according to the first group of line voltage values, the first group of current values, the second group of line voltage values, and the second group of current values; and determining, by the inverter according to an equivalent admittance matrix and the equivalent impedance matrix, whether a stability requirement of the inverter is met.

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Shanghai, China

Fangcheng Liu